Re: [PATCH] Btrfs: Add get/set label ioctl
From: Jie Liu <hidden>
Date: 2012-08-29 09:00:28
Hi Anand, I have posted a patch for set label back to last year, which can be found at: https://patchwork.kernel.org/patch/1124642/ Besides that, we have discussed to use 50 as the ioctl(2) number at that time. task assignment in our wiki page: https://btrfs.wiki.kernel.org/index.php/Project_ideas#Set.2Fchange_file_system_label Thanks, -Jeff On 08/29/12 16:46, Anand jain wrote:
quoted hunk ↗ jump to hunk
From: Anand Jain <redacted> Signed-off-by: Anand Jain <redacted> --- fs/btrfs/ctree.h | 10 ++++++++++ fs/btrfs/ioctl.c | 30 ++++++++++++++++++++++++++++++ fs/btrfs/ioctl.h | 2 ++ 3 files changed, 42 insertions(+), 0 deletions(-)diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 4bab807..eff506f 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h@@ -2583,6 +2583,16 @@ BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block, BTRFS_SETGET_STACK_FUNCS(super_cache_generation, struct btrfs_super_block, cache_generation, 64); +static inline char * btrfs_super_label(struct btrfs_super_block *s) +{ + return s->label; +} +static inline void btrfs_set_super_label(struct btrfs_super_block *s, + char *val) +{ + memcpy(s->label,val,BTRFS_LABEL_SIZE); +} + static inline int btrfs_super_csum_size(struct btrfs_super_block *s) { int t = btrfs_super_csum_type(s);diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 7bb7556..b472942 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c@@ -3687,6 +3687,32 @@ out: return ret; } +static int btrfs_ioctl_get_label(struct btrfs_root *root, void __user *arg) +{ + char *label; + label = btrfs_super_label(root->fs_info->super_copy); + if (copy_to_user(arg, label, BTRFS_LABEL_SIZE)) + return -EFAULT; + return 0; +} + +static int btrfs_ioctl_set_label(struct btrfs_root *root, void __user *arg) +{ + struct btrfs_trans_handle *trans; + char label[BTRFS_LABEL_SIZE+1]; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (copy_from_user(label, arg, BTRFS_LABEL_SIZE)) + return -EFAULT; + label[BTRFS_LABEL_SIZE] = '\0'; + trans = btrfs_start_transaction(root, 1); + btrfs_set_super_label(root->fs_info->super_copy, label); + btrfs_commit_transaction(trans, root); + + return 0; +} + long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) {@@ -3785,6 +3811,10 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_qgroup_create(root, argp); case BTRFS_IOC_QGROUP_LIMIT: return btrfs_ioctl_qgroup_limit(root, argp); + case BTRFS_IOC_GET_LABEL: + return btrfs_ioctl_get_label(root, argp); + case BTRFS_IOC_SET_LABEL: + return btrfs_ioctl_set_label(root, argp); } return -ENOTTY;diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h index 731e287..0c60fcb 100644 --- a/fs/btrfs/ioctl.h +++ b/fs/btrfs/ioctl.h@@ -453,4 +453,6 @@ struct btrfs_ioctl_send_args { struct btrfs_ioctl_qgroup_limit_args) #define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \ struct btrfs_ioctl_get_dev_stats) +#define BTRFS_IOC_GET_LABEL _IOR(BTRFS_IOCTL_MAGIC, 53, __u64) +#define BTRFS_IOC_SET_LABEL _IOW(BTRFS_IOCTL_MAGIC, 54, __u64) #endif